“You ask me what we need to win this war. I answer, tobacco as much as bullets.”

So cabled the commander of the American Expeditionary Force, Gen. John Pershing, to the War Department in 1917.

It’s a long way from “Black Jack” Pershing to Chuck Hagel. Not that the Obama administration shies away from wars. It’s just that the target is less likely to be the Russians or Iranians than our own troops: specifically, the soldiers, sailors, airmen and Marines who smoke.

This week, Defense Secretary Hagel announced he supports a ban on tobacco sales on bases and ships. This followed a memo sent to service chiefs earlier by two top Pentagon officials: “The prominence of tobacco products in retail outlets and permission for smoking breaks while on duty sustain the perception that we are not serious about reducing the use of tobacco.”

What a narrow view of the cigarette. For nearly a century, tobacco in its various forms has been, as Pershing appreciated, a powerful weapon in what we used to call the arsenal of freedom — a symbol of confidence, grit and resolve.

For Churchill, it was his cigar. For FDR, it was his cigarette in his holder, protruding upward from his upturned chin. For MacArthur, it was his corncob pipe.

So it was too for those lower down the command chain. The Vietnam grunt with a pack of Camels strapped to his helmet. The grizzled GI on Sai­pan who made it to the cover of Life magazine with his smoke clenched in his mouth. The shirtless sailor in his helmet and dogtags, taking a cigarette break on a corner of his ship.

Not to mention the Marine featured on the front page of The Post during the Second Battle of Fallujah.

Hollywood understood. Think of Robert Mitchum in “The Longest Day,” lighting up a celebratory stogie after the storming of Omaha Beach. Or Mitchum again, this time fighting on the Pacific front in “Heaven Knows, Mr. Allison,” where he is stranded with a nun (Deborah Kerr) on an island. As he’s carried out on a stretcher by fellow Marines who have retaken the island, the friendship between this odd pair is conveyed when Kerr takes his cigarette from his mouth so he can exhale.

Other such moments include John Wayne’s Sgt. Stryker sharing a pack of cigarettes in “The Sands of Iwo Jima” right before he takes a bullet in the back. Bill Holden in bed with Grace Kelly in “The Bridges at Toko-Ri,” having a cigarette before he ships out to the Korean War. Or Gary Sinise’s legless, cigarette-smoking Lt. Dan in “Forrest Gump.”

Nor are these the cigarette’s only contributions to the war effort. In 1945, a former British POW who would go on to become an economist with the International Monetary Fund wrote a famous article about how cigarettes became a currency in Stalag VII-A.

In the same way, an American survivor of the infamous Bataan Death March, Lester Tenney, wrote in “My Hitch In Hell” how Japanese cigarettes, the currency of choice in his Philippine camp, facilitated trade among the prisoners. “As Adam Smith predicted,” he wrote, “this economy made everyone better off.”

Cigarettes were also a means of compassion. We have countless images of men with faces covered in bandages or bodies mangled on the battlefield enjoying what one publication described as the “last and only solace of the wounded.”

And between enemies who shared neither language nor flag, the cigarette was often the only human bond. Consider the photo of a Marine on Iwo Jima offering a smoke to a Japanese who had tried to hide by burying himself in the sand. Another photo from World War I shows a Canadian soldier lighting the cigarette of a German prisoner.

All this we now seem bent on doing away with. Long ago we stopped including cigs in C-Rations. Later we (rightly) stopped subsidizing cigarette prices at the exchanges. But now we want to ban military sales altogether.

Question: When this doesn’t work, are we going to forbid people to bring smokes onto military installations — or send them to our troops in CARE packages?

In fairness, it didn’t start with Secretary Hagel. Over the years, the Pentagon has launched any number of anti-smoking campaigns. Still, it’s especially hard to take from an administration that justifies the move in the name of military readiness even as it is busy shrinking the Army to levels not seen since before Pearl Harbor.

Pity the Ukrainians never understood the realities of these new US priorities. If they had, they would have declared Crimea a “smoking-free zone” before Vladimir Putin invaded. And America might have taken the integrity of their borders more seriously.